Supercharger assembly for regeneration of throttling losses and method of control

ABSTRACT

An engine assembly is provided that includes an engine throttle and a supercharger placed in series with one another in air flow to the engine. The throttle and supercharger can be controlled so that throttling losses are selectively distributed across the throttle and/or the supercharger. Throttling losses placed across the supercharger can create torque that can be converted to stored energy.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/348,303 filed on 28 Mar. 2014, which is a National Stage Applicationof PCT/US2012/057702 filed on 28 Sep. 2012, which claims benefit of U.S.patent application Ser. No. 61/541,593 filed on 30 Sep. 2011 and U.S.patent application Ser. No. 61/683,939 filed on 16 Aug. 2012, and whichapplications are incorporated herein by reference. To the extentappropriate, a claim of priority is made to each of the above disclosedapplications.

TECHNICAL FIELD

The present teachings generally include a supercharger placed in serieswith an engine throttle.

BACKGROUND

Energy efficient engines of reduced size are desirable for fuel economyand cost reduction. Smaller engines provide less torque than largerengines. A supercharger is sometimes used to increase the torqueavailable from an engine. At low engine speeds, when higher torque isoften requested by a vehicle operator by depressing the acceleratorpedal, the supercharger provides additional air to the engine intakemanifold, boosting air pressure and thereby allowing the engine togenerate greater torque at lower engine speeds.

SUMMARY

The present teachings generally include an assembly for controlling airflow to an engine. The engine has engine cylinders and has an enginethrottle in a throttle body positioned in the air flow to the cylinders.The throttle and supercharger are controlled so the pressure drop thatoccurs across the throttle is selectively distributed across thethrottle and/or the supercharger. The pressure drop is due to the vacuumcreated by the reciprocating pistons in the engine cylinders and becauseof the inefficiency created by the turbulence in air flow around thethrottle at low throttle (i.e., only partially opened throttle)conditions. The energy associated with the pressure drop across thethrottle is typically unused, and so is referred to as “throttlinglosses”. In the assembly, the pressure drop can be placed across thesupercharger, causing torque on the supercharger that can be utilized(i.e., the throttling losses are “captured,” “regenerated,” or“recovered) such as by conversion to stored energy.

More specifically, an assembly for controlling air flow to an enginehaving a crankshaft, engine cylinders, and a throttle in a throttle bodyupstream in the air flow to the engine cylinders, includes asupercharger having a set of rotors in series with the throttle in theair flow to the engine. A gear arrangement has a first memberoperatively connected with a load device, a second member operativelyconnectable with the engine crankshaft, and a third member operativelyconnectable with the supercharger. The load device can be amotor/generator, but is not limited to such. The load device isselectively controllable to vary a speed of rotation of the rotorsthrough the gear arrangement to thereby cause the throttle to open. Apressure drop across the throttle then shifts to the rotors, creatingtorque on the rotors, throttling losses thereby being regenerated.

In one aspect of the present teachings, a controller is operativelyconnected to the motor/generator and is configured to control themotor/generator to alternately function as a motor and as a generator. Abattery is operatively connected to the controller and themotor/generator. The motor/generator can be controlled to function as agenerator to convert the torque on the rotors to energy stored in thebattery during periods of relatively constant engine speeds when thestate-of-charge of the battery reaches a predetermined first level untila state-of-charge of the battery reaches a predetermined second levelhigher than the first level. When the throttle is less open, so thatless of the pressure drop is distributed to the rotors, themotor/generator can then be controlled to function as a motor to providetorque at the crankshaft after the state-of-charge of the batteryreaches the predetermined second level until the state-of-charge of thebattery again reaches the predetermined first level.

The above features and advantages and other features and advantages ofthe present teachings are readily apparent from the following detaileddescription of the best modes for carrying out the present teachingswhen taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration in partial cross-sectional view of anassembly having an engine throttle and a supercharger in series, with aplanetary gear set and a motor/generator operatively connectable to thesupercharger in accordance with an aspect of the present teachings.

FIG. 2 is a schematic perspective illustration of a compound planetarygear set that may be used in place of the planetary gear set of FIG. 1in accordance with an alternative aspect of the present teachings.

FIG. 3 is a plot of a state-of-charge of a battery connected with themotor/generator of FIG. 1 versus time.

FIG. 4 is a plot of pressure drop across the throttle of FIG. 1 versustime.

FIG. 5 is a plot of pressure drop across the supercharger of FIG. 1versus time.

FIG. 6 is a schematic illustration of a vehicle having the assembly ofFIG. 1, depicting a first drive mode providing low end boost duringacceleration and a second drive mode providing boost during accelerationwith high power demand.

FIG. 7 is a schematic illustration of the vehicle of FIG. 6 depicting athird drive mode with hybrid functionality during vehicle cruising and afourth drive mode providing engine start/stop functionality andaccessory drive by the motor/generator when the engine is stopped.

FIG. 8 is a schematic illustration of the vehicle of FIGS. 6 and 7depicting a throttling loss regeneration mode.

FIG. 9 is a schematic illustration of the vehicle of FIGS. 6-8 depictinga regenerative braking mode.

FIG. 10 is a schematic illustration of the two-position clutch of FIG.1.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numbers refer to likecomponents throughout the several views, FIG. 1 shows an assembly 10that includes a supercharger 12 placed in series with a throttle 14 in athrottle body 16 in the air flow upstream of a plenum 18 in an engineair intake manifold 20 through which air is introduced into enginecylinders 15 of an engine 11. The throttle 14 is also referred to hereinas a throttle valve. Movement of pistons within the engine cylinders 15creates a vacuum that pulls the air through the plenum 18. The throttle14 is downstream in the air flow from the supercharger 12 and controlsair flow from the throttle body 16 to the engine cylinders 15. As usedherein, a first component is “downstream” in air flow from a secondcomponent if the direction of air flow requires that the air flow pastthe second component prior to the first component when air is directedpast both components. Similarly, a first component is “upstream” in airflow from a second component if the direction of air flow requires thatthe air flow past the first component prior to the second component whenair is directed past both components. The throttle 14 is showndownstream of the supercharger 12. It should be understood that thefunctionality of the supercharger 12 described herein can also beachieved if the supercharger 12 was positioned downstream of thethrottle 14. In either configuration, the throttle 14 and thesupercharger 12 are considered to be in series with one another in theair flow to the engine cylinders 15. Two components are “in series” withone another in the air flow to the engine 11 when air that flows pastone of the components subsequently flows past the other component.

The supercharger 12 can have a set of rotors with a first rotor 26 thatcan mesh with a second rotor 28. Each rotor 26, 28 can have multiplelobes. The supercharger 12 can boost the air pressure upstream of theplenum 18, forcing more air into the engine cylinders 15, and thusincreasing engine power. A bypass valve 34 can be selectively moveableto allow inlet air flowing through an air cleaner 21 (e.g., a filter) tobypass the supercharger 12 when engine boost is not desired. When thevalve 34 is in the closed position, no air flows through bypass passage35 so that the air inlet 74 to the rotors 26, 28 is not in fluidcommunication with the air outlet 78 of the rotors 26, 28 except throughthe supercharger 12, allowing the possibility of a pressure differentialto be established by the rotors 26, 28. In other words, when the valve34 is in a closed position, the air flow represented by arrows throughbypass passage 35 cannot occur. The engine 11 of the engine assembly 10is depicted schematically in FIGS. 6-9 as part of a vehicle 13.

The throttle 14 and the bypass valve 34 are shown as butterfly valvesthat are each pivotable about a respective pivot axis between a closedposition and an open position. In the closed position, the throttle 14or valve 34 is generally perpendicular to the walls of the respectivesurrounding throttle body 16 or bypass passage 35. In the fully openposition, the throttle 14 or valve 34 is generally parallel to the wallsof the respective surrounding throttle body 16 or bypass passage 35.This position is referred to as wide open throttle. The throttle 14 andbypass valve 34 can also be moved to a variety of intermediate positionsbetween the closed position and the open position. In FIG. 1, thethrottle 14 and valve 34 are each shown in an intermediate position. Acontroller 68A controls the operation of the throttle 14 and valve 34.The controller 68A can be an engine controller.

The supercharger 12 can be a fixed displacement supercharger, such as aRoots-type supercharger that outputs a fixed volume of air per rotation.The increased air output from the supercharger 12 then becomespressurized when forced into the air plenum 18. A Roots-typesupercharger is a volumetric device, and therefore is not dependent onrotational speed in order to develop pressure. The volume of airdelivered by the Roots-type supercharger per each rotation of thesupercharger rotors is constant (i.e., does not vary with speed). ARoots-type supercharger can thus develop pressure at low engine speedsbecause the Roots-type supercharger functions as a pump rather than as acompressor. Compression of the air delivered by the Roots-typesupercharger takes place downstream of the supercharger 12 in the engineplenum 18. Alternatively, the supercharger 12 can be a compressor, suchas a centrifugal-type supercharger that is dependent on rotational speedin order to develop pressure. A centrifugal-type supercharger compressesthe air as it passes through the supercharger but must run at higherspeeds than a Roots-type supercharger in order to develop apredetermined pressure.

The assembly 10 includes a gear arrangement that can be a planetary gearset 41 with a sun gear member 42, a ring gear member 44, and a carriermember 46 that rotatably supports a set of pinion gears 47 that can meshwith both the ring gear member 44 and the sun gear member 42. The enginecrankshaft 48 can rotate with the carrier member 46 through a belt drive49 when an engine disconnect clutch 55 is engaged to connect thecrankshaft 48 with a shaft 59 rotatable by a pulley 83A that isdrivingly engaged with a belt 82 of the belt drive 49. The enginedisconnect clutch 55 is also referred to herein as a third clutch.

An electric motor/generator 50 can have a rotatable motor shaft 52 witha rotatable gear 54 mounted on the motor shaft 52. The motor/generator50 is a load device as it can create a load when acting as a generatorto convert torque to electric energy stored in a battery 66, and canapply a torque load when acting as a motor. The load is a variable loadbecause the speed of the motor/generator 50 can be controlled. The motorshaft 52 is driven by a motor rotor 63. A stator 65 is mounted to astationary member 64, such as a motor casing. The rotatable gear 54 canmesh with the ring gear member 44. The sun gear member 42 can beconnectable for rotation with the first rotor 26 of the supercharger 12.The second rotor 28 also rotates when the first rotor 26 rotates due toa set of intermeshing gears 51, 53. Gear 51 is connected for rotationwith the first rotor 26 and meshes with gear 53, which is connected forrotation with the second rotor 28.

The belt drive 49 may be referred to as a front engine accessory drive(FEAD) as vehicle electrical devices 80, such as electrical accessories,may also be driven by the belt 82 of the belt drive 49 either via theengine crankshaft 48 when clutch 55 is engaged and may be driven by themotor/generator 50 when the clutch 55 is not engaged, such as during anengine start/stop mode discussed herein with respect to FIG. 7, when theengine 11 is off. A pulley 83B is drivingly engaged with the belt 82 anda shaft 86 rotates with the pulley 83B to drive the electrical devices80. Another pulley 83C is drivingly engaged with the belt 82 and drivesa shaft 88 connected with the carrier 46.

In certain aspects of the present teachings, the gear arrangement can bea compounded dual planetary gear set 141 as shown in FIG. 2, that canhave two ring gear members 144A, 144B, two sun gear members 142A, 142B,and a common carrier member 146 that can support a first set of piniongears 147A that can mesh with one of the ring gear members 144A and oneof the sun gear members 142A, and a second set of pinion gears 147B thatcan mesh with the other ring gear member 144B and the other sun gearmember 142B. Although each set of pinion gears 147A, 147B includesmultiple pinion gears, only one pinion gear of each set of pinion gears147A, 147B is shown for clarity in the drawing. The engine crankshaft 48of FIG. 1 can rotate commonly with or can be connected through the beltdrive 49 to the input sun gear member 142. A motor/generator like thatof FIG. 1 can have a motor shaft that rotates with a rotatable gear 154that can mesh with the input side ring gear member 144A. The rotatablegear 154 is clutched like gear 54 of FIG. 1. The ring gear member 144Bis grounded to a stationary member 64B (i.e., a non-rotating member),such as the engine block. The sun gear member 142B can be connectablefor rotation with the first rotor 26 of the supercharger 12 of FIG. 1.

The sun gear member 42 of FIG. 1 (or the output sun gear member 142B ofthe alternate dual planetary gear set 141 of FIG. 2) can be selectivelyconnectable with the first rotor 26 of the supercharger 12 by control ofa two-position clutch 57 that can connect the sun gear member 42 with ashaft 62 that rotates with and can drive the rotor 26. The two-positionclutch 57 is also referred to herein as a first clutch. The two-positionclutch 57 can be controllable by an electronic controller 68B and anactuator 94 to move between two alternate positions as shown in FIG. 10.In a first position, the clutch 57 grounds the sun gear member 42 ofFIG. 1 or the output sun gear member 142B of FIG. 2 to the stationarymember 64A such as the engine block. When the clutch 57 is in the firstposition, the planetary gear set 41 or 141 is not operatively connectedto the supercharger 12. In a second position, the clutch 57 connects thesun gear member 42 or 142A for common rotation (i.e., rotation at thesame speed) as the first rotor 26 of the supercharger 12.

FIG. 10 shows the two-position clutch 57 of FIG. 1 in greater detail.The clutch 57 includes a reaction plate 81 splined to an extension 84that is splined to the shaft 62. The reaction plate 81 is supported on ashaft 86 by a bearing 85. The sun gear member 42 is mounted on or formedwith the shaft 86 and rotates with the shaft 86. A spring 89 containedin a spring housing 90 biases a friction plate 92 into engagement withthe reaction plate 81. When the friction plate 92 is engaged with thereaction plate 81 as shown in FIG. 10, the clutch 57 is in the secondposition and the shaft 62 is thereby connected to rotate at the samespeed as the sun gear member 42 through the clutch 57. The clutch 57includes an actuator 94 with a coil 96 held in a coil support 98 mountedto a stationary member 64A, such as a housing for the gear set 41. Abattery 66A can be controlled by a controller 68B to selectivelyenergize the coil 96. The battery 66A and controller 68B can be separatefrom the battery 66 and controller 68 used to control themotor/generator 50. Alternatively, the same battery 66 and controller 68can be used to control the clutch 57. When the coil 96 is energized, thefriction plate 92 is pulled toward the coil 96 by magnetic force to afirst position 92A, shown in phantom. The magnetic force of theenergized coil 96 overcomes the force of the spring 89, and the spring89 is compressed by the friction plate 92. In the first position 92A,the friction plate 92 is held to the stationary member 64A, braking thesun gear member 42. The friction plate 92 is not in contact with thereaction plate 82 in the first position, so that shaft 62 is not heldstationary by the clutch 57.

As shown in FIG. 1, a battery 66 can be used to provide electric powerto the motor/generator 50 when the motor/generator 50 is controlled tofunction as a motor, and to receive electrical power from themotor/generator 50 when the motor/generator 50 is controlled to functionas a generator. Vehicle electrical devices 80 can also draw electricpower from the battery 66. A controller 68 can control the functioningof the motor/generator 50 as a motor or as a generator. A power inverter70 can be used to convert the energy supplied by the motor/generator 50from alternating current to direct current to be stored in the battery66 when the motor/generator 50 operates as a generator, and from directcurrent to alternating current when the motor/generator 50 operates as amotor.

The first rotor 26 of the supercharger 12 is connected to rotate withthe sun gear member 42 when the two-position clutch 57 is in the secondposition. When in this state, a pressure differential is created acrossthe supercharger 12 from the air inlet 74 at the first rotor 26 to theair outlet 78 at the second rotor 28. As described below, the two-wayclutch 57, and the bypass valve 34 can be selectively controlled toprovide a desired intake air pressure to the engine cylinders whileallowing the supercharger 12 and the motor/generator 50 to be used toprovide regenerative electrical energy to the battery 66 for providingpower to vehicle electrical devices and/or for providing torque at thecrankshaft 48 when the motor/generator 50 is controlled to function as amotor.

In a first vehicle drive mode, also referred to as a low end boostingmode that can be implemented during vehicle acceleration, the engine 11can drive the vehicle 13 as indicated by arrow A in FIG. 6 extendingfrom the engine 11 through the vehicle transmission 61 to the wheelaxle. The engine 11 can provide tractive torque to the vehicle wheels 60at one or both wheel axles, depending on the vehicle drivetrain. Boostcan be provided by airflow through the supercharger 12 to the engine 11.When engine boost is demanded, the throttle 14 can move to a relativelymore open position than shown in FIG. 1, such as in response todepression of an accelerator pedal. The rotors 26, 28 can effectivelyoperate as a pump to increase air flow to the throttle body 16 andplenum 18 to meet operator demand. With the two-position clutch 57grounded, the motor/generator 50 can be controlled to function as amotor or as a generator providing continuously variable transmissionfunctionality to vary the torque at the crankshaft 48.

In a second vehicle drive mode, also indicated in FIG. 6, when highpower is demanded during vehicle acceleration, the engine 11 can drivethe vehicle wheels 60, as indicated by arrow A, and also drive thesupercharger 12 when the clutch 57 is in the second position, asindicated by arrows B and C, thereby providing additional boost. Themotor/generator 50 can be controlled to operate as a motor to adjust theboost by varying the speed of the ring gear member 44 of the geararrangement 41 (shown in FIG. 1 and represented in FIG. 6 as a speedcoupling device), as indicated by arrow D in FIG. 6.

When engine boost is not desired, the throttling losses (i.e., thepressure drop associated with the vacuum created by the moving enginecylinders) can be applied across both the throttle 14 and thesupercharger 12 with the bypass valve 34 closed. The position of thethrottle 14 can be balanced with the pressure drop desired across thesupercharger 12 and air flows through both the supercharger 12 and pastthe at least partially closed throttle 14 to reach the engine cylinders15. Alternatively, the bypass valve 34 can be closed so that all airflow to the engine 11 must flow through the supercharger 12. Theposition of the bypass valve 34 can be controlled to allow fastadjustments in the air flow to the engine 11 when necessary to allow atleast some air to bypass the supercharger 12. The two-position clutch 57can be placed in the second position so that torque generated by thepressure drop across the supercharger 12 will be applied to the sun gearmember 42, and thus to the engine crankshaft 48 and also to themotor/generator 50 (when powered) via the torque split provided by theplanetary gear set 41. This operating mode can be referred to as athrottling loss regeneration mode, and is shown schematically in FIG. 8with recaptured throttling losses represented as arrow E used to addpower to the engine crankshaft 48 when clutch 55 is engaged and clutch57 is in the second position. Alternately or in addition, all or aportion of the recaptured throttling losses can be used to recharge thebattery 66 when the motor/generator 50 is controlled to function as agenerator, as indicated by arrow F.

The torque load applied by the motor/generator 50 functioning as agenerator can be shown to effectively slow down the speed of the rotors26, 28, causing the throttle 14 to open and thereby apply a pressuredifferential across the rotors 26, 28. That is, the vacuum created bythe reciprocating pistons in the engine cylinders 15 is moved from thethrottle 14 to the rotors 26, 28 when the throttle 14 is opened. Theresulting pressure drop from the inlet 74 to the outlet 78 of the rotors26, 28 creates torque at the rotors 26, 28. The rotors 26, 28 caneffectively function as an air motor, extracting torque that istransferred through the planetary gear set 41 and allowing it to beconverted to stored electrical energy by the motor/generator 50. Duringthe throttling loss regeneration mode, the engine 11 can be used topower the vehicle 13 by providing tractive torque to the wheels 60, asindicated by arrow G.

Thus, at least a portion of the throttling losses can be captured aselectrical energy stored in a battery 66 attached to the motor/generator50 and/or as mechanical energy to be applied to the engine crankshaft48. The motor/generator 50 can be controlled to operate as a generatorwhen it is desired to charge the battery 66. This will slow thesupercharger 12, and so is best implemented during vehicle operatingconditions when boost is not needed, such as, but not limited to, duringvehicle cruising at an engine speed of 1500 revolutions per minute (rpm)and a state-of-charge of the battery 66 less than a predeterminedmaximum state-of-charge threshold, allowing additional electric energyto be stored. When the state-of-charge of the battery 66 reaches apredetermined maximum level, such as but not limited to 100 percent ofthe charge attainable by the battery 66, the two-position clutch 57 canbe placed in the first position to ground the sun gear member 42. Thesupercharger 12 will then freewheel. The throttle 14 can be adjusted bya controller to a position that will maintain the desired air pressurein the engine (downstream of the throttle) as all pressure drops will beacross the throttle 14 when the two-position clutch 57 is in the firstposition. Alternatively, the clutch 57 can be designed only as a braketo stop the supercharger first rotor 26, requiring the bypass 34 toopen, allowing air to bypass the supercharger 12 and flow to thethrottle 14. The motor/generator 50 can be controlled to function as amotor to apply torque to the engine crankshaft 48, thus reducing thestate-of-charge of the battery 66 and using the energy that wasrecaptured in the battery 66 via the supercharger 12. Various sensorscan be used to provide crankshaft 48 torque information and battery 66state-of-charge data to the controller 68.

When the battery state-of-charge then falls to a predetermined minimumlevel, such as but not limited to 80 percent of the charge attainable bythe battery 66, the two-position clutch 57 can then be moved to thesecond position and the motor/generator 50 can again be controlled tooperate as a generator so that torque is supplied through the planetarygear set 41 from the supercharger 12 to the motor/generator 50 andconverted to electrical energy stored in the battery 66. When thestate-of-charge again reaches the maximum level, the two-position clutch57 can be moved back to the first position, the motor/generator 50 canoperate as a motor to provide torque to the crankshaft 48, thesupercharger 12 freewheels, and the throttle 14 can be adjusted tomaintain the desired engine air pressure. This hybrid operating modeavailable during vehicle cruising is depicted schematically in FIG. 7.When clutch 55 is closed, the motor/generator 50 can thus cycle betweenfunctioning as a motor to provide power to the engine crankshaft 48 asindicated by arrow H using the stored energy from the capturedthrottling losses, and functioning as a generator to recharge thebattery 66 of FIG. 7 during the cruising mode. The engine 11 alsoprovides power to the vehicle wheels 60, as indicated by arrow J.

The cycle of controlling the two-position clutch 57, the throttle 14,and the motor/generator 50 during cruising is illustrated in FIGS. 3-5.FIG. 3 shows the cycle of charging (positive slope) and dissipatingenergy (negative slope) in the battery 66 with the state-of-charge 200varying between a predetermined minimum level 202 (i.e., a predeterminedfirst level) and a predetermined maximum level 204 (i.e., apredetermined second level) as time progresses. FIG. 4 shows thepressure drop across the throttle 14 that corresponds with the chargingand dissipating of the battery 66. The pressure drop 206 across thethrottle 14 is relatively low at level 208 when the battery 66 ischarging, as the throttle 14 is moved to a more open position when someof the total pressure drop is placed across the supercharger 12. Thepressure drop across the throttle 14 is at a relatively high level 210,with the throttle 14 being adjusted to a less open position, when thebattery 66 is dissipating as the supercharger 12 is freewheeling and allpressure drop necessary to maintain the desired engine air pressure isacross the throttle 14.

The period 218 of the cycle shown in FIG. 3 can be adjusted bycontrolling the torque load of the motor/generator 50 when operated as agenerator to a lower level, thus charging the battery 66 at a slowerrate, or by increasing the range between the minimum level 202 of thestate-of-charge and the maximum level 204 of the state-of-charge. Thepressure drop 212 across the supercharger 12 is relatively high at level214 when the battery 66 is charging, as the throttle 14 is moved to amore open position when some of the total pressure drop is placed acrossthe supercharger 12. The pressure drop across the supercharger 12 is ata relatively low level 216, with the throttle 14 being adjusted to aless open position, when the battery 66 is dissipating as thesupercharger 12 is freewheeling and all pressure drop necessary tomaintain the desired engine air pressure is across the throttle 14.

In another aspect of the present teachings, as an alternative to cyclingbetween a maximum and a minimum state-of-charge of the battery 66 duringvehicle cruising, the motor/generator 50 can be controlled so that therate of electrical energy regenerated is balanced against the energyused by the vehicle electrical components, keeping the state-of-chargein the battery 66 relatively constant. The regeneration rate andassociated torque drag by the motor/generator 50 can be balanced againsttorque applied by the supercharger 12 to the engine crankshaft 48 toavoid or minimize the cyclical charging and dissipating pattern duringvehicle cruising.

In lieu of a motor/generator 50, one or more alternative controllableload devices can be operatively connected at the ring gear member 44 or144B of FIG. 2. For example, an accumulator with a hydraulic orpneumatic pump, a slippable friction clutch, or a spring can beoperatively connected to the ring gear member 44 or 144B and can becontrolled to capture throttling loss energy via the supercharger 12. Inthe case of an accumulator, the energy can be stored as hydraulic orpneumatic pressure. In the case of a slippable friction clutch, theenergy can be converted to heat by slipping the clutch, and can then becaptured for use in vehicle heating and cooling systems. The loadapplied by the motor/generator 50, accumulator, spring, or slippingclutch can also slow the sun gear member 42 or 142B and connectedsupercharger 12, and can be controlled to manage air flow into theengine especially at high speeds when there can be excess air flow tothe engine.

Additionally, the motor/generator 50 can be controlled to function as amotor to start the engine when the two-position clutch 57 is placed inthe first position to ground the sun gear member 42 or 142B and theclutch 55 is engaged. FIG. 7 illustrates the engine start-stop mode witharrow H depicting powerflow from the motor/generator 50 to start theengine 11. For example, if the engine 11 is shutoff at a stop light, themotor/generator 50 can be used to restart the engine. Thus, fuel savingscan be realized during the period that the engine 11 is shutoff, andrestarting the engine can be accomplished with the electric energygenerated from recaptured throttling losses. The engine can providetorque to charge the motor/generator 50 through the planetary gear set41 or 141 when the motor/generator 50 is controlled to function as agenerator and the two-position clutch 57 is in the first position toground the sun gear member 42.

The crankshaft 48 can provide torque to run the supercharger 12 throughthe planetary gear set 41 when a selectively engageable dog clutch 79 isengaged to ground the gear member 54 to the stationary member 64, thusalso holding the ring gear member 44 and the motor/generator 50stationary. The dog clutch 79 is also referred to herein as a secondclutch. Alternatively, the motor/generator 50 can be held stationary byapplying torque to stall the motor/generator 50 through the control ofelectrical energy to the motor/generator 50. However, the dog clutch 79can be used to avoid the use of stored electrical energy to hold themotor/generator 50 stationary. Additionally, braking energy can berecaptured in a regenerative braking mode, with torque at the crankshaft48 being recaptured as stored energy in the battery 66 when themotor/generator 50 is controlled to function as a generator and theclutch 55 is engaged. The regenerative braking mode is schematicallydepicted in FIG. 9 with arrow K representing energy from the wheels 60to the battery 66.

The reference numbers used in the drawings and the specification and thecorresponding components are as follows:

-   10 assembly-   11 engine-   12 supercharger-   13 vehicle-   14 throttle-   15 cylinder-   16 throttle body-   18 plenum-   20 manifold-   21 air cleaner-   26 first rotor-   28 second rotor-   34 bypass valve-   35 bypass passage-   41 planetary gear set-   42 sun gear member-   44 ring gear member-   46 carrier member-   47 pinion gears-   48 crankshaft-   49 belt drive-   50 motor/generator-   51 gear-   52 motor shaft-   53 gear-   54 rotatable gear-   55 engine disconnect clutch-   57 two-position clutch-   59 shaft-   60 wheels-   61 transmission-   62 shaft-   63 motor rotor-   64A stationary member-   64B stationary member-   65 stator-   66 battery-   68 controller-   68A controller-   68B controller-   70 inverter-   74 air inlet-   78 air outlet-   79 dog clutch-   80 vehicle electrical devices-   81 reaction plate-   82 belt-   83A pulley-   83B pulley-   83C pulley-   84 extension-   85 bearing-   86 shaft-   88 shaft-   89 spring-   90 spring housing-   92 friction plate-   92A first position-   94 actuator-   96 coil-   98 coil support-   141 compound dual-planetary gear set-   142A sun gear member-   142B sun gear member-   144A ring gear member-   144B ring gear member-   146 carrier-   147A pinion gears-   147B pinion gears-   154 rotatable gear-   200 state-of-charge-   202 predetermined first minimum level-   204 predetermined second maximum level-   206 throttle pressure drop-   208 low pressure level-   210 high pressure level-   212 supercharger pressure drop-   214 high pressure level-   216 low pressure level-   218 period

While the best modes for carrying out the many aspects of the presentteachings have been described in detail, those familiar with the art towhich these teachings relate will recognize various alternative aspectsfor practicing the present teachings that are within the scope of theappended claims.

1-20. (canceled)
 21. An assembly for controlling air flow to an enginehaving a crankshaft, cylinders and a throttle in a throttle bodypositioned in air flow to the cylinders, the assembly comprising: asupercharger having a set of rotors in series with the throttle in theair flow to the engine; a load device; and a gear arrangement having afirst member operatively connected with the load device, a second memberoperatively connectable with the crankshaft, and a third memberoperatively connectable with the supercharger; wherein the load deviceis selectively controllable to vary a speed of rotation of the rotorsthrough the gear arrangement to thereby cause the throttle to open sothat a pressure drop across the throttle shifts to the rotors, creatingtorque on the rotors, throttling losses thereby being regenerated. 22.The assembly of claim 21, further comprising a clutch controllable tomove between a first position and a second position, wherein the clutchis operable to ground the third member with a stationary member when inthe first position and to operatively connect the third member with therotors when in the second position so that the torque on the rotors isprovided to the load device through the gear arrangement when the clutchis in the second position.
 23. The assembly of claim 22, wherein theclutch is a first clutch, and further comprising: a second clutchselectively engageable to operatively connect the first member to astationary member, thereby holding the first member stationary; and athird clutch selectively engageable to operatively connect thecrankshaft with the second member; wherein at least a portion of thetorque on the rotors is applied to the crankshaft through the geararrangement when the first clutch is in the second position and thesecond and third clutches are engaged.
 24. The assembly of claim 23,wherein the load device is a motor/generator operable to alternatelyfunction as a motor and as a generator; and further comprising: acontroller configured to control the motor/generator to alternativelyfunction as a motor and as a generator; wherein the motor/generator iscontrolled by the controller to function as a motor when the firstclutch is in the first position, the second clutch is not engaged, andthe third clutch is engaged, thereby applying torque to the crankshaftthrough the gear arrangement to start the engine.
 25. The assembly ofclaim 22, wherein the clutch is a first clutch, and further comprising:a second clutch selectively engageable to operatively connect the firstmember to a stationary member, thereby holding the first memberstationary; and a third clutch selectively engageable to operativelyconnect the crankshaft with the second member; wherein the enginethereby drives the supercharger through the gear arrangement when thefirst clutch is in the second position and the second and third clutchesare engaged.
 26. The assembly of claim 21, wherein the load device is amotor/generator operable to selectively function as a motor or as agenerator, and further comprising: a controller configured to controlthe motor/generator to alternatively function as a motor and as agenerator; a first clutch controllable to move between a first positionand a second position, wherein the first clutch is operable to groundthe third member with a stationary member when in the first position andto operatively connect the third member with the rotors when in thesecond position; a second clutch selectively engageable to operativelyconnect the first member to a stationary member, thereby holding thefirst member stationary; and a third clutch selectively engageable tooperatively connect the crankshaft with the second member, the enginedriving the supercharger through the gear arrangement to provide engineboost and the controller controlling the motor/generator to vary a speedof the third member to thereby vary the engine boost when the firstclutch is in the second position, the third clutch is engaged, and thesecond clutch is not engaged.
 27. The assembly of claim 21, furthercomprising: a first clutch controllable to move between a first positionand a second position, wherein the first clutch is operable to groundthe third member with a stationary member when in the first position andto connect the third member to rotate with the rotors when in the secondposition; a second clutch selectively engageable to operatively connectthe first member to a stationary member, thereby holding the firstmember stationary; a third clutch selectively engageable to operativelyconnect the crankshaft with the second member; and a controller; whereinthe load device is a motor/generator operable, and the controller isconfigured to control the motor/generator selectively as a motor or as agenerator; and wherein the motor/generator is controlled by thecontroller to function as a generator when the first clutch is in thefirst position, the second clutch is not engaged, and the third clutchis engaged to thereby provide torque from the crankshaft through thegear arrangement to the generator in a regenerative braking mode. 28.The assembly of claim 21, wherein the first member is a ring gearmember, the second member is a carrier member, and the third member is asun gear member.
 29. The assembly of claim 28, wherein the load deviceis a motor/generator operable to alternately function as a motor and asa generator.
 30. The assembly of claim 29, further comprising: acontroller operatively connected to the motor/generator and configuredto control the motor/generator to alternately function as a motor and asa generator; and a battery operatively connected to the controller andthe motor/generator; wherein the throttle is open and themotor/generator is controlled to function as a generator to convert thetorque on the rotors to energy stored in the battery during constantengine speeds when a state-of-charge of the battery reaches apredetermined first level and until the state-of-charge of the batteryreaches a predetermined second level higher than the predetermined firstlevel, and the throttle is less open and the motor/generator iscontrolled to function as a motor to provide torque at the crankshaftwhen the state-of-charge of the battery reaches the predetermined secondlevel until the state-of-charge of the battery again reaches thepredetermined first level.
 31. The assembly of claim 29, furthercomprising: a controller operatively connected to the motor/generatorand configured to control the motor/generator to alternately function asa motor and as a generator; and a battery operatively connected to thecontroller and the motor/generator and configured to store energyconverted from the torque on the rotors by the motor/generator when themotor/generator is controlled to function as a generator; wherein atleast one vehicle electrical device is operatively connected to thebattery and is configured to receive stored energy from the battery; andwherein a rate of energy stored in the battery that is converted fromthe torque at the rotors is equal to the rate of stored energy in thebattery received as electrical power by said at least one vehicleelectrical device.
 32. An assembly for controlling air flow to an enginehaving a crankshaft, cylinders and a throttle in a throttle bodypositioned in air flow to the cylinders, the assembly comprising: asupercharger having a set of rotors in series with the throttle in theair flow to the engine; a load device; and a planetary gear arrangementhaving a first gear arrangement operatively connected with the loaddevice, a second gear arrangement operatively connectable with thecrankshaft, and a third gear arrangement operatively connectable withthe supercharger; wherein the load device is selectively controllable tovary a speed of rotation of the rotors through the gear arrangement tothereby cause the throttle to open so that a pressure drop across thethrottle shifts to the rotors, creating torque on the rotors, throttlinglosses thereby being regenerated.
 33. The assembly of claim 32, whereinthe first gear arrangement is a ring gear, the second gear arrangementis a carrier gear arrangement and the third gear arrangement is a sungear.
 34. The assembly of claim 32, wherein the load device is amotor/generator operable to alternately function as a motor and as agenerator.
 35. The assembly of claim 32, further comprising a clutchcontrollable to move between a first position and a second position,wherein the clutch is operable to ground the third gear arrangement witha stationary member when in the first position and to operativelyconnect the third gear arrangement with the rotors when in the secondposition so that the torque on the rotors is provided to the load devicethrough the planetary gear arrangement when the clutch is in the secondposition.
 36. The assembly of claim 35, wherein the clutch is a firstclutch, and further comprising: a second clutch selectively engageableto operatively connect the first gear arrangement to a stationarymember, thereby holding the first gear arrangement stationary; and athird clutch selectively engageable to operatively connect thecrankshaft with the second gear arrangement; wherein the engine therebydrives the supercharger through the planetary gear arrangement when thefirst clutch is in the second position and the second and third clutchesare engaged.
 37. An assembly for controlling air flow to an enginehaving a crankshaft, cylinders and a throttle in a throttle bodypositioned in air flow to the cylinders, the assembly comprising: asupercharger having a set of rotors in series with the throttle in theair flow to the engine; a motor/generator configured to alternatelyfunction as a motor and as a generator; and a planetary gear arrangementhaving a ring gear arrangement operatively connected with the loaddevice, a carrier gear arrangement operatively connectable with thecrankshaft, and a sun gear arrangement operatively connectable with thesupercharger; wherein the load device is selectively controllable tovary a speed of rotation of the rotors through the planetary geararrangement to thereby cause the throttle to open so that a pressuredrop across the throttle shifts to the rotors, creating torque on therotors, throttling losses thereby being regenerated.
 38. The assembly ofclaim 37, further comprising a clutch controllable to move between afirst position and a second position, wherein the clutch is operable toground the sun gear arrangement with a stationary member when in thefirst position and to operatively connect the sun gear arrangement withthe rotors when in the second position so that the torque on the rotorsis provided to the load device through the planetary gear arrangementwhen the clutch is in the second position.
 39. The assembly of claim 38,wherein the clutch is a first clutch, and further comprising: a secondclutch selectively engageable to operatively connect the ring geararrangement to a stationary member, thereby holding the ring geararrangement stationary; and a third clutch selectively engageable tooperatively connect the crankshaft with the carrier gear arrangement;wherein the engine thereby drives the supercharger through the planetarygear arrangement when the first clutch is in the second position and thesecond and third clutches are engaged.
 40. The assembly of claim 39,further comprising: a controller configured to control themotor/generator.